L720 imei null and no sound

hi for all
am have GS4 L720 with imei null .
phone with 4.4.2 sound is work but with any downgrade firmware sound not work and imei still null after flash
L720VPUFNAE_L720SPTFNAE and flash modem NAE-ModemOnly.tar still imei null am have some box software am reset efs but still the same problem please help me how to return imei

hi for all
am have GS4 L720 with imei null .
phone with 4.4.2 sound is work but with any downgrade firmware sound not work and imei still null after flash
L720VPUFNAE_L720SPTFNAE and flash modem NAE-ModemOnly.tar still imei null am have some box software am reset efs but still the same problem please help me how to return imei

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